Medical treatment of various illnesses or diseases commonly includes the use of one or more medical devices. Two types of medical devices that are commonly used to repair various types of body passageways are an expandable graft or stent, or a surgical graft. These devices have been implanted in various areas of the mammalian anatomy.
Old age, dietary habits and primary genetics can also lead to a common disease, atherosclerosis. Atherosclerotic plaques and blockages consist of lipids, fibroblasts and fibrin that proliferate and cause obstruction of a vessel. As the obstruction grows, the blood flow diminishes and reaches a level that is insufficient to meet the biological needs of one or more organs. The end result is defined as ischemia.
One purpose of a stent is to open a blocked or partially blocked body passageway. When a stent is used in a blood vessel, the stent is used to open the occluded vessel to achieve improved blood flow which is necessary to provide for the anatomical function of an organ. The procedure of opening a blocked or partially blocked body passageway commonly includes the use of one or more stents in combination with other medical devices such as, but not limited to, an introducer sheath, a guiding catheter, a guide wire, an angioplasty balloon, etc.
The use of stents in blood vessels and other structures in the body has become a well established clinical procedure over the past several years. The equipment and techniques for deploying stents inside blood vessels are well established. There are very few dedicated devices or techniques available for stenting the ostium of blood vessels. Most stents currently available are very difficult to position in the ostium of arteries; since the stent is either inserted too far leaving a critical portion of a lesion uncovered, or the stent protrudes too far out into a major blood vessel such as the aorta or the left main coronary artery. This problem occurs with balloon expandable, as well as self-expanding stents.
Several stents are known to the art. MacGregor, U.S. Pat. No. 4,994,071, discloses a stent having an enlarged end (bifurcation). Maginot, U.S. Pat. No. 5,456,712, discloses a flanged stent member. Mori, U.S. Pat. No. 5,466,242, discloses a shape memory alloy stent where a portion of the stent linearly flares in a funnel/conical shape to hold the stent in place. Lam, U.S. Pat. No. 5,607,444 discloses a specialized ostial stent for repairing vessels at bifurcations. Yadav, U.S. Pat. No. 6,293,964 discloses a specialized ostial stent having a plurality of flat flaring members that are used to hold the stent in the ostia. All of the above-identified stent designs and methodology of use are incorporated herein by reference.